At least 43 people died when a ferry capsized off Zanzibar, but around 300 people are feared still missing, a minister in the semi-autonomous archipelago said Saturday.
"So far we have recovered 43 people who died, but we have rescued 259 survivors," said Mohammed Aboud, Zanzibar's state minister for emergencies, adding that 40 of those rescued were seriously injured.
Officials said that around 600 people were believed to have been on the stricken ferry, including families returning home after the holidays to celebrate the end of the Muslim holy month of Ramadan.
The exact number of passengers on this type of ferry is often difficult to establish as no reliable passenger lists are kept.
"We have asked for emergency assistance from Dar es Salaam, including divers, to help in the rescue efforts," Aboud told AFP.
The MV Spice Islander, which was travelling between Zanzibar's main island Unguja and Pemba, two of the three islands that make up Zanzibar, had left Unguja around 9:00 pm (1800 GMT) and capsized four hours later.
It was reportedly carrying a heavy cargo of rice and other goods. "Rescue operations are being hampered by a lack of equipment," deputy secretary of state for infrastructure and communication Issa Gavu told AFP.
However, survivors have begun arriving back in Stone Town, the main port and capital of the archipelago, with an emergency first aid centre set up in the port to treat those arriving by rescue speed boat from the capsized boat.
No foreigners have so far been reported amongst either the dead or rescued, according to an AFP reporter at the scene.
Ferries have a poor safety record in Tanzania. In May 2009, a ferry capsized leaving six people dead, while several fires on cargo boats have been reported in recent years.
Tourism is the main foreign currency earner for Zanzibar, famed for its white-sand beaches and historical buildings in Stone Town, listed as a world heritage site by UNESCO, the United Nations cultural organization.
Pemba lies some 80 kilometres (50 miles) north-west of Unguja